dom-is-fast.js

function render(obj) {
  if (typeof obj === 'string') {
    return new Text(obj);
  } else if (Array.isArray(obj)) {
    if (obj[0] === '!comment') {
      return new Comment(obj[1]);
    }
    var dom = document.createElement(obj[0]);
    var attrs = obj[1];
    var keys = Object.keys(attrs);
    var i, len;
    for (i = 0, len = keys.length; i < len; i++) {
      dom.setAttribute(keys[i], attrs[keys[i]]);
    }
    for (i = 2, len = obj.length; i < len; i++) {
      dom.appendChild(render(obj[i]));
    }
    return dom;
  } else {
    throw 'Cannot make dom of: ' + obj;
  }
}

var tmp, target;
var js = ['div', {}];
var i = 100;
while (--i) { js.push(['span', {'class': 'some classes'}, Array(100).join('Hello world!')]); }

var dom = render(js);
var html = dom.outerHTML;

i = 1e4;
target = document.createElement('div');
console.time('dom');
while (--i) {
  target.appendChild(render(js));
  target.removeChild(target.firstChild);
}
console.timeEnd('dom');

i = 1e4;
target = document.createElement('div');
console.time('innerHTML');
while (--i) {
  target.innerHTML = html;
}
console.timeEnd('innerHTML');;